Cranes C
- 1. Cranes
- 2. Major Causes of Crane Accidents Contact with power lines Overturns Falls Mechanical failures
- 3. Instability – unsecured load, load capacity exceeded, or ground not level or too soft Lack of communication - the point of operation is a distance from the crane operator or not in full view of the operator Lack of training Inadequate maintenance or inspection How Do Accidents Occur?
- 4. Who is at Risk Operators Persons at Crane Site
- 5. Definitions Crane – Consists of a rotating structure for lifting and lowering horizontally on rubber tires or crawler treads Hoist - Used to lift and lower load. Boom – An inclined spar, strut, or other long member supporting the hoisting tackle Boom stops – A device used to limit the angle of the boom at its highest position Brake – To slow or stop motion by friction or power Block – Sheaves or grooved pulleys in a frame with hook, eye and strap Jib – Extension attached to the boom point to provide added boom length for lifting specified loads.
- 6. Crane Parts
- 7. Types of Cranes Mobile Hydraulic Overhead Gantry Tower
- 8. Improper load rating Excessive speeds No hand signals Inadequate inspection and maintenance Unguarded parts Unguarded swing radius Crane Hazards Working too close to power lines Improper exhaust system Shattered windows No steps/guardrails walkways No boom angle indicator Not using outriggers
- 9. Planning Before Start-Up Level the crane and ensure support surface is firm and able to support the load Contact power line owners and determine precautions. Know the location and voltage of overhead power lines. Know the basic crane capacities, limitations, and job site restrictions, such as the location of power lines, unstable soil, or high winds. Make other personnel aware of hoisting activities. Barricade areas within swing radius. Ensure proper maintenance and inspections. Determine safe areas to store materials and place machinery.
- 10. Competent Person The competent person must inspect all machinery and equipment prior to each use, and during use, to make sure it is in safe operating condition. If it needs fixing, take it out of service and don’t use it until it is fixed Broken Track
- 11. Make sure the crane operator can see the: Rated Load Capacities Operating Speeds Special Hazard Warning or Instruction Load Capacity - Speed - Warnings Load Rating Chart
- 12. Know the Weight of the Load Refer to shipping ticket or other documentation Ensure lift calculations are correct Ensure load is within load chart rating for boom length and load radius of crane Crane is rated by the maximum weight it will lift at a minimum radius and minimum boom length – the further from its centerpoint, the less it will lift
- 13. Load Limiting Factors Not level Wind Side loads On its wheels Lifting over the side Use of extensions, jibs and other attachments Limits of wire rope, slings and lifting devices
- 14. Mobile Cranes – Lifting Principles Center of Gravity Leverage Stability Structural Integrity
- 15. Load Example – 30 ton crane Will lift 60,000 pounds at 10 feet from the center pin of the crane Based on level surface, no wind, and outriggers fully extended At 25 feet from the center pin with an 80 foot boom, the capacity is only 14,950 pounds At 74 feet from the center pin, the capacity is only 4,800 pounds
- 16. Improper Load Improper loads or speeds can result in the tipping of the crane
- 17. Improper Load
- 18. Improper Load
- 19. Stay clear from power lines at least 10 feet Power Lines
- 20. An illustration of the signals must be posted at the job site Hand Signals
- 21. Guard Moving Parts Unguarded Chain Drive Guard moving parts such as gears or belts
- 22. Swing Radius Swing Radius Stay out of the swing radius of the crane – Make sure there are barrier guards showing swing radius
- 23. Operator Visibility Broken Window Make sure broken windows or other obstructions do not prevent the operator from seeing
- 24. Ladders Ladder Use ladders to get to the upper portion of the cab
- 25. Guardrails Runways and steps need to have guardrails, handholds and slip resistant surfaces
- 26. Suspended Loads Don’t stand under suspended loads
- 27. Boom Angle Indicator A boom angle indicator must be on the crane
- 28. Supporting Surface Cranes must be on a firm supporting surface and level within 1 percent
- 29. The grooves must be smooth and free from surface defects which could cause rope damage Sheaves
- 30. Rigging Equipment Slings Types of slings include alloy steel chain, wire rope, metal mesh, natural or synthetic fiber rope, and synthetic web. Chain Wire rope Metal mesh Synthetic
- 31. Annual Inspections Inspection of the hoisting machinery must be made by a competent person The employer must maintain a record of these inspections Crane wasn’t inspected and tipped over
- 32. What to Inspect Correct air pressure and no leaks Tires properly inflated Clearance for tail swing Wire rope wear Physical damage to crane Loose or missing hardware, nuts, or bolts Fluid leaks
- 33. Remove From Service Immediately remove damaged or defective slings from service
- 34. Damaged wire rope Broken Strands Damaged wire rope must be taken out of service Crushed Rope
- 35. Worn Part
- 36. Conduct regular inspections of tires for excessive wear or damage Tire Inspections
- 37. Training Operators: must qualify on specific crane type Must include on-the-job training Supervisor / competent person
- 38. Summary An unstable load, lack of communication, lack of training, and inadequate maintenance or inspection are major contributors to crane accidents. Operators or others working in the area can be victims to “struck by" and "caught in" injuries. Contact with power lines causes many accidents. A competent person must inspect a crane regularly to insure it is in proper order. Planning and training reduces accidents.
Editor's Notes
- #2: 1926 Subpart N – Cranes, Derricks, Hoists, Elevators, and Conveyors This presentation is designed to assist trainers conducting OSHA 10-hour Construction Industry outreach training for workers. Since workers are the target audience, this presentation emphasizes hazard identification, avoidance, and control – not standards. No attempt has been made to treat the topic exhaustively. It is essential that trainers tailor their presentations to the needs and understanding of their audience. This presentation is not a substitute for any of the provisions of the Occupational Safety and Health Act of 1970 or for any standards issued by the U.S. Department of Labor. Mention of trade names, commercial products, or organizations does not imply endorsement by the U.S. Department of Labor. Other standards and references used for this presentation are as follows: Mobile Hydraulic Crane Standards - PCSA Standard NO. 2 - Power Crane and Shovel Association 2. USA Standards - Safety Code for Cranes, Derricks, Hoists, Jacks and Slings - Crawler, locomotive and truck cranes - USAS B30.5-1968